Ink jet apparatus

Abstract

A drop emitting device that includes a drop generator and a drive signal waveform that includes in sequence a pulse of a first polarity, a first pulse of a second polarity, a delay interval, and a second pulse of the second polarity.

1. A drop emitting device comprising:
 a drop generator; 
 a drop firing waveform applied to the drop generator during a drop firing interval; 
 the drop firing waveform including in sequence a pulse of a first polarity, a first pulse of a second polarity, a delay interval, and a second pulse of the second polarity, wherein the second polarity is different from the first polarty. 
 
     
     
       2. The drop emitting device of  claim 1  wherein the drop generator comprises a piezo transducer. 
     
     
       3. The drop emitting device of  claim 1  wherein the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted. 
     
     
       4. The drop emitting device of  claim 1  wherein:
 the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted; and 
 the second pulse of the second polarity is configured to dissipate residual energy remaining in the drop generator after a drop is emitted. 
 
     
     
       5. The drop emitting device of  claim 1  wherein:
 the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted; and 
 the second pulse of the second polarity is configured to prevent breakage of a meniscus in the drop generator after a drop is emitted. 
 
     
     
       6. The drop emitting device of  claim 1  wherein the delay is in the range of about 2 microseconds to about 7 microseconds. 
     
     
       7. The drop emitting device of  claim 1  wherein the drop generator is operated at a drop firing frequency of at least about 10 KHz. 
     
     
       8. The drop emitting device of  claim 1  wherein the drop generator is operated at a drop firing frequency in the range of about 10 KHz to about 40 KHz. 
     
     
       9. The drop emitting device of  claim 1  wherein the first pulse of the second polarity has a duration that is less than a duration of the pulse of the first polarity. 
     
     
       10. The drop emitting device of  claim 1  wherein the second pulse of the second polarity has a duration that is less than a duration of the pulse of the first polarity. 
     
     
       11. The drop emitting device of  claim 1  wherein the second pulse of the second polarity has a duration that is less than a duration of the first pulse of the second polarity. 
     
     
       12. The drop emitting device of  claim 1  wherein the second pulse of the second polarity has a generally triangular shape. 
     
     
       13. The drop emitting device of  claim 1  wherein the second pulse of the second polarity has a generally trapezoidal shape. 
     
     
       14. The drop emitting device of  claim 1  wherein the pulse of the first polarity has a magnitude in the range of about 33 volts to about 47 volts. 
     
     
       15. The drop emitting device of  claim 1  wherein the pulse of the first polarity has a magnitude of no more than about 39 volts. 
     
     
       16. The drop emitting device of  claim 1  wherein the first pulse of the second polarity has a peak magnitude in the range of about 30 volts to about 47 volts. 
     
     
       17. The drop emitting device of  claim 1  wherein the first pulse of the second polarity has a peak magnitude no more than about 35 volts. 
     
     
       18. The drop emitting device of  claim 1  wherein the second pulse of the second polarity has a peak magnitude in the range of about 15 volts to about 47 volts. 
     
     
       19. The drop emitting device of  claim 1  wherein the second pulse of the second polarity has a peak amplitude that is no more than about 22 volts. 
     
     
       20. The drop emitting device of  claim 1  wherein the second pulse of the second polarity has a peak amplitude that is less than a peak amplitude of the first pulse of the second polarity. 
     
     
       21. A drop emitting device comprising:
 a piezoelectric drop generator; 
 a drop firing waveform applied to the piezoelectric drop generator during a drop firing interval; and 
 the drop firing waveform including in sequence a pulse of a first polarity having a peak magnitude in the range of about 33 volts to about 47 volts, a first pulse of a second polarity having a peak magnitude in the range of about 30 volts to about 47 volts, a delay interval, and a second pulse of the second polarity having a peak magnitude in the range of about 15 volts to about 47 volts, wherein the second polarity is different from the first polarity. 
 
     
     
       22. The drop emitting device of  claim 21  wherein the drop generator comprises a piezo transducer. 
     
     
       23. The drop emitting device of  claim 21  wherein the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted. 
     
     
       24. The drop emitting device of  claim 21  wherein:
 the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted; and 
 the second pulse of the second polarity is configured to dissipate residual energy remaining in the drop generator after a drop is emitted. 
 
     
     
       25. The drop emitting device of  claim 21  wherein:
 the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted; and 
 the second pulse of the second polarity is configured to prevent breakage of a meniscus in the drop generator after a drop is emitted. 
 
     
     
       26. The drop emitting device of  claim 21  wherein the delay is in the range of about 2 microseconds to about 7 microseconds. 
     
     
       27. The drop emitting device of  claim 21  wherein the first pulse of the second polarity has a duration that is less than a duration of the pulse of the first polarity. 
     
     
       28. The drop emitting device of  claim 21  wherein the second pulse of the second polarity has a duration that is less than a duration of the pulse of the first polarity. 
     
     
       29. The drop emitting device of  claim 21  wherein the second pulse of the second polarity has a duration that is less than a duration of the first pulse of the second polarity. 
     
     
       30. The drop emitting device of  claim 21  wherein the second pulse of the second polarity has a generally triangular shape. 
     
     
       31. The drop emitting device of  claim 21  wherein the second pulse of the second polarity has a generally trapezoidal shape. 
     
     
       32. The drop emitting device of  claim 21  wherein the pulse of the first polarity has a magnitude of no more than about 39 volts. 
     
     
       33. The drop emitting device of  claim 21  wherein the first pulse of the second polarity has a peak magnitude no more than about 35 volts. 
     
     
       34. The drop emitting device of  claim 21  wherein the second pulse of the second polarity has a peak amplitude that is no more than about 22 volts. 
     
     
       35. The drop emitting device of  claim 21  wherein the second pulse of the second polarity has a peak amplitude that is less than a peak amplitude of the first pulse of the second polarity. 
     
     
       36. A drop emitting device comprising:
 a piezoelectric drop generator; 
 a drop firing waveform applied to the piezoelectric drop generator during a drop firing interval; and 
 the drop firing waveform including in sequence a pulse of a first polarity having a duration in the range of about 10 microseconds to about 16 microseconds, a first pulse of second polarity having a duration in the range of about 3 microseconds to about 7 microseconds, a delay interval in the range of about 2 to about 7 microseconds, and a second pulse of the second polarity having a duration in the range of about 2 microseconds to about 8 microseconds, wherein the second polarity is different from the first polarity. 
 
     
     
       37. The drop emitting device of  claim 36  wherein the drop generator comprises a piezo transducer. 
     
     
       38. The drop emitting device of  claim 36  wherein the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted. 
     
     
       39. The drop emitting device of  claim 36  wherein:
 the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted; and 
 the second pulse of the second polarity is configured to dissipate residual energy remaining in the drop generator after a drop is emitted. 
 
     
     
       40. The drop emitting device of  claim 36  wherein:
 the pulse of the first polarity and the first pulse of the second polarity are configured to cause a drop to be emitted; and 
 the second pulse of the second polarity is configured to prevent breakage of a meniscus in the drop generator after a drop is emitted. 
 
     
     
       41. The drop emitting device of  claim 36  wherein the second pulse of the second polarity has a duration that is less than a duration of the first pulse of the second polarity. 
     
     
       42. The drop emitting device of  claim 36  wherein the second pulse of the second polarity has a generally triangular shape. 
     
     
       43. The drop emitting device of  claim 36  wherein the second pulse of the second polarity has a generally trapezoidal shape. 
     
     
       44. The drop emitting device of  claim 36  wherein the pulse of the first polarity has a magnitude in the range of about 33 volts to about 47 volts. 
     
     
       45. The drop emitting device of  claim 36  wherein the pulse of the first polarity has a magnitude of no more than about 39 volts. 
     
     
       46. The drop emitting device of  claim 36  wherein the first pulse of the second polarity has a peak magnitude in the range of about 30 volts to about 47 volts. 
     
     
       47. The drop emitting device of  claim 36  wherein the first pulse of the second polarity has a peak magnitude no more than about 35 volts. 
     
     
       48. The drop emitting device of  claim 36  wherein the second pulse of the second polarity has a peak magnitude in the range of about 15 volts to about 47 volts. 
     
     
       49. The drop emitting device of  claim 38  wherein the second pulse of the second polarity has a peak amplitude that is no more than about 22 volts. 
     
     
       50. The drop emitting device of  claim 36  wherein the second pulse of the second polarity has a peak amplitude that is less than a peak amplitude of the first pulse of the second polarity.